A three dimensional (3D) range camera determines distances to features in a scene that it images and may provide the distances in a range image, also referred to as a 3D image. The range image, or 3D image, may comprise three spatial coordinates for each of a plurality of features in the scene relative to an origin of coordinates located at the camera. Active illumination range cameras provide range images of scenes that they image based at least in part on light reflected by features in the scenes from light that the cameras transmit to illuminate the scenes. A time of flight (TOF) active illumination range camera transmits modulated light to illuminate a scene that it images and modulates sensitivity of the range camera to register light reflected by features in the scene from the transmitted light. An amount of light that the TOF range camera registers from a given feature in the scene is proportional to a cross correlation of light reflected by the feature from the transmitted light that reaches the camera and the time modulated camera exposure periods during which the camera registers light. The TOF range camera determines a round trip time for light to travel from the camera to the feature and back to the camera based on the amount of reflected light that the camera registers for the feature and uses the round trip time and the speed of light to determine distance to the feature.
Whereas active illumination range cameras were originally relatively scarce and limited to technical, engineering, and scientific applications, active illumination range imaging technology has matured, and range cameras are frequent components of a continually expanding catalog of consumer products. Range cameras may be found not only in video game consoles, but laptop computers, workbooks, tablets, smartphones, and even wrist watches.